mull over vs excogitate

mull over and excogitate both are verbs.

Word	Noun	Adjective	Verb	Adverb
mull over	No	No	Yes	No
excogitate	No	No	Yes	No

As verbs, mull over and excogitate are synonyms defined as:

Other synonyms of mull over include chew over, contemplate, meditate, mull, muse, ponder, reflect, ruminate, speculate, think over.

mull over (verb)	excogitate (verb)
reflect deeply on a subject	reflect deeply on a subject
	come up with (an idea, plan, explanation, theory, or principle) after a mental effort